1
|
Song G, Xu B, Shi H, Zhang Y, Zhang D, Cao X, Liu Z, Guo R, Guan YZ, Chu Y, Zhang X, Lou J, Qin Y. Conformational activation of ribosome recycling by intra- and inter-molecular dynamics of RRF. Int J Biol Macromol 2020; 160:1212-1219. [DOI: 10.1016/j.ijbiomac.2020.05.254] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Revised: 05/21/2020] [Accepted: 05/27/2020] [Indexed: 12/18/2022]
|
2
|
Licatalosi DD, Ye X, Jankowsky E. Approaches for measuring the dynamics of RNA-protein interactions. WILEY INTERDISCIPLINARY REVIEWS. RNA 2020; 11:e1565. [PMID: 31429211 PMCID: PMC7006490 DOI: 10.1002/wrna.1565] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Revised: 07/20/2019] [Accepted: 07/25/2019] [Indexed: 12/17/2022]
Abstract
RNA-protein interactions are pivotal for the regulation of gene expression from bacteria to human. RNA-protein interactions are dynamic; they change over biologically relevant timescales. Understanding the regulation of gene expression at the RNA level therefore requires knowledge of the dynamics of RNA-protein interactions. Here, we discuss the main experimental approaches to measure dynamic aspects of RNA-protein interactions. We cover techniques that assess dynamics of cellular RNA-protein interactions that accompany biological processes over timescales of hours or longer and techniques measuring the kinetic dynamics of RNA-protein interactions in vitro. This article is categorized under: RNA Interactions with Proteins and Other Molecules > Protein-RNA Interactions: Functional Implications RNA Interactions with Proteins and Other Molecules > Protein-RNA Recognition RNA Interactions with Proteins and Other Molecules > RNA-Protein Complexes RNA Evolution and Genomics > Ribonomics.
Collapse
Affiliation(s)
- Donny D Licatalosi
- Center for RNA Science and Therapeutics, School of Medicine, Case Western Reserve University, Cleveland, Ohio
| | - Xuan Ye
- Center for RNA Science and Therapeutics, School of Medicine, Case Western Reserve University, Cleveland, Ohio
| | - Eckhard Jankowsky
- Center for RNA Science and Therapeutics, School of Medicine, Case Western Reserve University, Cleveland, Ohio
| |
Collapse
|
3
|
Mathews DH. How to benchmark RNA secondary structure prediction accuracy. Methods 2019; 162-163:60-67. [PMID: 30951834 DOI: 10.1016/j.ymeth.2019.04.003] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2018] [Revised: 03/24/2019] [Accepted: 04/01/2019] [Indexed: 11/18/2022] Open
Abstract
RNA secondary structure prediction is widely used. As new methods are developed, these are often benchmarked for accuracy against existing methods. This review discusses good practices for performing these benchmarks, including the choice of benchmarking structures, metrics to quantify accuracy, the importance of allowing flexibility for pairs in the accepted structure, and the importance of statistical testing for significance.
Collapse
Affiliation(s)
- David H Mathews
- Center for RNA Biology, Department of Biochemistry & Biophysics, and Department of Biostatistics & Computational Biology, University of Rochester Medical Center, 601 Elmwood Avenue, Box 712, Rochester, NY 14642, United States.
| |
Collapse
|
4
|
Dao EH, Poitevin F, Sierra RG, Gati C, Rao Y, Ciftci HI, Akşit F, McGurk A, Obrinski T, Mgbam P, Hayes B, De Lichtenberg C, Pardo-Avila F, Corsepius N, Zhang L, Seaberg MH, Hunter MS, Liang M, Koglin JE, Wakatsuki S, Demirci H. Structure of the 30S ribosomal decoding complex at ambient temperature. RNA (NEW YORK, N.Y.) 2018; 24:1667-1676. [PMID: 30139800 PMCID: PMC6239188 DOI: 10.1261/rna.067660.118] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Accepted: 08/14/2018] [Indexed: 05/29/2023]
Abstract
The ribosome translates nucleotide sequences of messenger RNA to proteins through selection of cognate transfer RNA according to the genetic code. To date, structural studies of ribosomal decoding complexes yielding high-resolution data have predominantly relied on experiments performed at cryogenic temperatures. New light sources like the X-ray free electron laser (XFEL) have enabled data collection from macromolecular crystals at ambient temperature. Here, we report an X-ray crystal structure of the Thermus thermophilus 30S ribosomal subunit decoding complex to 3.45 Å resolution using data obtained at ambient temperature at the Linac Coherent Light Source (LCLS). We find that this ambient-temperature structure is largely consistent with existing cryogenic-temperature crystal structures, with key residues of the decoding complex exhibiting similar conformations, including adenosine residues 1492 and 1493. Minor variations were observed, namely an alternate conformation of cytosine 1397 near the mRNA channel and the A-site. Our serial crystallography experiment illustrates the amenability of ribosomal microcrystals to routine structural studies at ambient temperature, thus overcoming a long-standing experimental limitation to structural studies of RNA and RNA-protein complexes at near-physiological temperatures.
Collapse
Affiliation(s)
- E Han Dao
- Stanford PULSE Institute, SLAC National Laboratory, Menlo Park, California 94025, USA
| | - Frédéric Poitevin
- Stanford PULSE Institute, SLAC National Laboratory, Menlo Park, California 94025, USA
- Department of Structural Biology, Stanford University, Palo Alto, California 94305, USA
| | - Raymond G Sierra
- Stanford PULSE Institute, SLAC National Laboratory, Menlo Park, California 94025, USA
- Linac Coherent Light Source, SLAC National Laboratory, Menlo Park, California 94025, USA
| | - Cornelius Gati
- Department of Structural Biology, Stanford University, Palo Alto, California 94305, USA
- Biosciences Division, SLAC National Laboratory, Menlo Park, California 94025, USA
| | - Yashas Rao
- Stanford PULSE Institute, SLAC National Laboratory, Menlo Park, California 94025, USA
- Linac Coherent Light Source, SLAC National Laboratory, Menlo Park, California 94025, USA
| | - Halil Ibrahim Ciftci
- Stanford PULSE Institute, SLAC National Laboratory, Menlo Park, California 94025, USA
| | - Fulya Akşit
- Stanford PULSE Institute, SLAC National Laboratory, Menlo Park, California 94025, USA
| | - Alex McGurk
- Linac Coherent Light Source, SLAC National Laboratory, Menlo Park, California 94025, USA
| | - Trevor Obrinski
- Linac Coherent Light Source, SLAC National Laboratory, Menlo Park, California 94025, USA
| | - Paul Mgbam
- Linac Coherent Light Source, SLAC National Laboratory, Menlo Park, California 94025, USA
| | - Brandon Hayes
- Linac Coherent Light Source, SLAC National Laboratory, Menlo Park, California 94025, USA
| | - Casper De Lichtenberg
- Institutionen för Kemi, Kemiskt Biologiskt Centrum, Umeå Universitet, SE-901 87 Umeå, Sweden
| | - Fatima Pardo-Avila
- Department of Structural Biology, Stanford University, Palo Alto, California 94305, USA
| | - Nicholas Corsepius
- Department of Structural Biology, Stanford University, Palo Alto, California 94305, USA
| | - Lindsey Zhang
- Linac Coherent Light Source, SLAC National Laboratory, Menlo Park, California 94025, USA
| | - Matthew H Seaberg
- Linac Coherent Light Source, SLAC National Laboratory, Menlo Park, California 94025, USA
| | - Mark S Hunter
- Linac Coherent Light Source, SLAC National Laboratory, Menlo Park, California 94025, USA
| | - Mengling Liang
- Linac Coherent Light Source, SLAC National Laboratory, Menlo Park, California 94025, USA
| | - Jason E Koglin
- Linac Coherent Light Source, SLAC National Laboratory, Menlo Park, California 94025, USA
| | - Soichi Wakatsuki
- Department of Structural Biology, Stanford University, Palo Alto, California 94305, USA
- Biosciences Division, SLAC National Laboratory, Menlo Park, California 94025, USA
| | - Hasan Demirci
- Stanford PULSE Institute, SLAC National Laboratory, Menlo Park, California 94025, USA
- Department of Structural Biology, Stanford University, Palo Alto, California 94305, USA
- Biosciences Division, SLAC National Laboratory, Menlo Park, California 94025, USA
| |
Collapse
|
5
|
Van Dyken JD. Propagation and control of gene expression noise with non-linear translation kinetics. J Theor Biol 2017; 430:185-194. [PMID: 28709943 DOI: 10.1016/j.jtbi.2017.07.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2017] [Revised: 07/04/2017] [Accepted: 07/10/2017] [Indexed: 10/19/2022]
Abstract
Gene expression is a stochastic process involving small numbers of molecules. As a consequence, cells in a clonal population vary randomly and sometimes substantially from one another in the concentration of mRNA and protein species, a phenomenon known as gene expression noise. Previous theoretical models of gene expression noise assumed that translation is first-order (linear) in mRNA concentration, leading to unfiltered propagation of mRNA noise to the protein level. Here I consider the biological ramifications of relaxing this assumption. Specifically, I solve for the noise statistics of gene expression assuming that translation obeys hyperbolic, Michaelis-Menten kinetics with respect to mRNA concentration. I generalize previous stochastic gene expression models by allowing the kinetic order of translation, denoted here by a, to vary continuously from zero-order (a = 0), where ribosomes are fully saturated with mRNA, to first order (a = 1), where ribosomes are unsaturated and mRNA is limiting for translation. In general, hyperbolic translation acts as a high-amplitude filter of mRNA noise. This hyperbolic filtering greatly attenuates the propagation of transcriptional noise to the protein level and qualitatively changes the selective and synthetic targets of noise control. In principle, natural selection or synthetic biologists could exploit this feature to limit or amplify gene expression noise by tuning mRNA and ribosome levels to control the kinetic order of translation.
Collapse
Affiliation(s)
- J David Van Dyken
- Department of Biology, University of Miami, Coral Gables, FL 33146, United States.
| |
Collapse
|
6
|
Dršata T, Réblová K, Beššeová I, Šponer J, Lankaš F. rRNA C-Loops: Mechanical Properties of a Recurrent Structural Motif. J Chem Theory Comput 2017; 13:3359-3371. [DOI: 10.1021/acs.jctc.7b00061] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Tomáš Dršata
- Institute
of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo nám. 2, 166 10 Prague, Czech Republic
- Institute
of Biophysics, Academy of Sciences of the Czech Republic, Královopolská
135, 612 65 Brno, Czech Republic
| | - Kamila Réblová
- CEITEC—Central European Institute of Technology, Campus Bohunice, Kamenice 5, 625 00 Brno, Czech Republic
| | - Ivana Beššeová
- Institute
of Biophysics, Academy of Sciences of the Czech Republic, Královopolská
135, 612 65 Brno, Czech Republic
| | - Jiří Šponer
- Institute
of Biophysics, Academy of Sciences of the Czech Republic, Královopolská
135, 612 65 Brno, Czech Republic
- CEITEC—Central European Institute of Technology, Campus Bohunice, Kamenice 5, 625 00 Brno, Czech Republic
| | - Filip Lankaš
- Institute
of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo nám. 2, 166 10 Prague, Czech Republic
- Laboratory
of Informatics and Chemistry, University of Chemistry and Technology Prague, Technická 5, 166 28 Prague, Czech Republic
| |
Collapse
|
7
|
Noel JK, Chahine J, Leite VBP, Whitford PC. Capturing transition paths and transition states for conformational rearrangements in the ribosome. Biophys J 2016; 107:2881-2890. [PMID: 25517153 DOI: 10.1016/j.bpj.2014.10.022] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2014] [Revised: 09/25/2014] [Accepted: 10/16/2014] [Indexed: 11/26/2022] Open
Abstract
To reveal the molecular determinants of biological function, one seeks to characterize the interactions that are formed in conformational and chemical transition states. In other words, what interactions govern the molecule's energy landscape? To accomplish this, it is necessary to determine which degrees of freedom can unambiguously identify each transition state. Here, we perform simulations of large-scale aminoacyl-transfer RNA (aa-tRNA) rearrangements during accommodation on the ribosome and project the dynamics along experimentally accessible atomic distances. From this analysis, we obtain evidence for which coordinates capture the correct number of barrier-crossing events and accurately indicate when the aa-tRNA is on a transition path. Although a commonly used coordinate in single-molecule experiments performs poorly, this study implicates alternative coordinates along which rearrangements are accurately described as diffusive movements across a one-dimensional free-energy profile. From this, we provide the theoretical foundation required for single-molecule techniques to uncover the energy landscape governing aa-tRNA selection by the ribosome.
Collapse
Affiliation(s)
- Jeffrey K Noel
- Center for Theoretical Biological Physics, Rice University, Houston, Texas
| | - Jorge Chahine
- Instituto de Biociências, Letras e Ciências Exatas, Universidade Estadual Paulista, São José do Rio Preto, Brazil
| | - Vitor B P Leite
- Instituto de Biociências, Letras e Ciências Exatas, Universidade Estadual Paulista, São José do Rio Preto, Brazil
| | | |
Collapse
|
8
|
Tinoco I, Kim HK, Yan S. Frameshifting dynamics. Biopolymers 2016; 99:1147-66. [PMID: 23722586 DOI: 10.1002/bip.22293] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2013] [Revised: 05/14/2013] [Accepted: 05/20/2013] [Indexed: 01/26/2023]
Abstract
Translation of messenger RNA by a ribosome occurs three nucleotides at a time from start signal to stop. However, a frameshift means that some nucleotides are read twice or some are skipped, and the following sequence of amino acids is completely different from the sequence in the original frame. In some messenger RNAs, including viral RNAs, frameshifting is programmed with RNA signals to produce specific ratios of proteins vital to the replication of the organism. The mechanisms that cause frameshifting have been studied for many years, but there are no definitive conclusions. We review ribosome structure and dynamics in relation to frameshifting dynamics provided by classical ensemble studies, and by new single-molecule methods using optical tweezers and FRET.
Collapse
Affiliation(s)
- Ignacio Tinoco
- Department of Chemistry, University of California, Berkeley, Berkeley, CA, 94720-1460
| | | | | |
Collapse
|
9
|
Liu B, Qian SB. Characterizing inactive ribosomes in translational profiling. ACTA ACUST UNITED AC 2016; 4:e1138018. [PMID: 27335722 DOI: 10.1080/21690731.2015.1138018] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2015] [Revised: 12/20/2015] [Accepted: 12/28/2015] [Indexed: 01/10/2023]
Abstract
The broad impact of translational regulation has emerged explosively in the last few years in part due to the technological advance in genome-wide interrogation of gene expression. During mRNA translation, the majority of actively translating ribosomes exist as polysomes in cells with multiple ribosomes loaded on a single transcript. The importance of the monosome, however, has been less appreciated in translational profiling analysis. Here we report that the monosome fraction isolated by sucrose sedimentation contains a large quantity of inactive ribosomes that do not engage on mRNAs to direct translation. We found that the elongation factor eEF2, but not eEF1A, stably resides in these non-translating ribosomes. This unique feature permits direct evaluation of ribosome status under various stress conditions and in the presence of translation inhibitors. Ribosome profiling reveals that the monosome has a similar but not identical pattern of ribosome footprints compared to the polysome. We show that the association of free ribosomal subunits minimally contributes to ribosome occupancy outside of the coding region. Our results not only offer a quantitative method to monitor ribosome availability, but also uncover additional layers of ribosome status needed to be considered in translational profiling analysis.
Collapse
Affiliation(s)
- Botao Liu
- Division of Nutritional Sciences, Cornell University, Ithaca, NY, USA; Graduate Field of Genetics, Genomics, and Development, Cornell University, Ithaca, NY, USA; Present address: Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA, USA
| | - Shu-Bing Qian
- Division of Nutritional Sciences, Cornell University, Ithaca, NY, USA; Graduate Field of Genetics, Genomics, and Development, Cornell University, Ithaca, NY, USA
| |
Collapse
|
10
|
Serebrov V, Moore MJ. Single Molecule Approaches in RNA-Protein Interactions. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 907:89-106. [DOI: 10.1007/978-3-319-29073-7_4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
|
11
|
Whitford PC. The ribosome's energy landscape: Recent insights from computation. Biophys Rev 2015; 7:301-310. [PMID: 28510226 PMCID: PMC5418421 DOI: 10.1007/s12551-014-0155-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2014] [Accepted: 11/25/2014] [Indexed: 01/25/2023] Open
Abstract
The ever-increasing capacity of computing resources has extended ribosome calculations from the study of small-scale fluctuations to large-scale barrier-crossing processes. As the field of computational/theoretical biophysics shifts focus to large-scale conformational transitions, there is a growing need for a systematic framework to interpret and analyze ribosome dynamics. To this end, energy landscape principles, largely developed for the study of biomolecular folding, have proven to be invaluable. These tools not only provide a foundation for describing simulations but can be used to reconcile experimental results, as well. In this review, I will discuss recent efforts to employ computational methods to reveal the characteristics of the ribosome's landscape and how these studies can help guide a new generation of experiments that more closely probe the underlying energetics. As a result of these investigations, general principles about ribosome function are beginning to emerge, including that: (1) small-scale fluctuations are the result of structure, rather than detailed energetics, (2) molecular flexibility leads to entropically favored rearrangements, and (3) tRNA dynamics may be accurately described as diffusive movement across an energy landscape.
Collapse
Affiliation(s)
- Paul Charles Whitford
- Department of Physics, Northeastern University Dana Research Center 123, 360 Huntington Ave, Boston, MA, 02115, USA.
| |
Collapse
|
12
|
Xie P. Ribosome utilizes the minimum free energy changes to achieve the highest decoding rate and fidelity. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2015; 92:022716. [PMID: 26382441 DOI: 10.1103/physreve.92.022716] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2015] [Indexed: 06/05/2023]
Abstract
The performance of ribosome translation can be characterized by two factors, the translation rate and fidelity. Here, we provide analytical studies of the effect of the near-cognate tRNAs on the two factors. It is shown that the increase of the concentration of the near-cognate tRNAs relative to that of the cognate tRNA has negative effects on the ribosome translation by reducing both the translation rate and the translation fidelity. The effect of the near-cognate ternary complexes on the translation rate results mainly from the initial selection phase, whereas the proofreading phase has a minor effect. By contrast, the effect of the near-cognate ternary complexes on the fidelity results almost equally from the two phases. By using two successive phases, the initial selection and the proofreading, the ribosome can achieve higher translation fidelity than the product of the fidelity when only the initial selection is included and when only the proofreading is included, especially at the large ratio of the concentration of the near-cognate tRNAs compared to that of the cognate tRNA. Moreover, we study the changes of the free energy landscape in the tRNA decoding step. It is found that the rate constants of the tRNA decoding step measured experimentally give the minimum energy changes for the ribosomal complex to attain the optimal performance with both the highest decoding rate and fidelity and/or with the maximum value of the decoding fitness function. This suggests that the ribosome has evolved to utilize the minimum free energy changes gained from the conformational changes of the ribosome, EF-Tu, and tRNA to achieve the optimal performance in the tRNA decoding.
Collapse
Affiliation(s)
- Ping Xie
- Key Laboratory of Soft Matter Physics and Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| |
Collapse
|
13
|
Behrmann E, Loerke J, Budkevich TV, Yamamoto K, Schmidt A, Penczek PA, Vos MR, Bürger J, Mielke T, Scheerer P, Spahn CMT. Structural snapshots of actively translating human ribosomes. Cell 2015; 161:845-57. [PMID: 25957688 PMCID: PMC4432480 DOI: 10.1016/j.cell.2015.03.052] [Citation(s) in RCA: 136] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2014] [Revised: 01/05/2015] [Accepted: 02/27/2015] [Indexed: 10/23/2022]
Abstract
Macromolecular machines, such as the ribosome, undergo large-scale conformational changes during their functional cycles. Although their mode of action is often compared to that of mechanical machines, a crucial difference is that, at the molecular dimension, thermodynamic effects dominate functional cycles, with proteins fluctuating stochastically between functional states defined by energetic minima on an energy landscape. Here, we have used cryo-electron microscopy to image ex-vivo-derived human polysomes as a source of actively translating ribosomes. Multiparticle refinement and 3D variability analysis allowed us to visualize a variety of native translation intermediates. Significantly populated states include not only elongation cycle intermediates in pre- and post-translocational states, but also eEF1A-containing decoding and termination/recycling complexes. Focusing on the post-translocational state, we extended this assessment to the single-residue level, uncovering striking details of ribosome-ligand interactions and identifying both static and functionally important dynamic elements.
Collapse
Affiliation(s)
- Elmar Behrmann
- Institut für Medizinische Physik und Biophysik, Charité-Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany
| | - Justus Loerke
- Institut für Medizinische Physik und Biophysik, Charité-Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany
| | - Tatyana V Budkevich
- Institut für Medizinische Physik und Biophysik, Charité-Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany
| | - Kaori Yamamoto
- Institut für Medizinische Physik und Biophysik, Charité-Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany
| | - Andrea Schmidt
- Institut für Medizinische Physik und Biophysik, Charité-Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany; Institut für Medizinische Physik und Biophysik, AG Protein X-Ray Crystallography, Charité-Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany
| | - Pawel A Penczek
- Department of Biochemistry and Molecular Biology, The University of Texas Medical School, 6431 Fannin MSB 6.220, Houston, TX 77054, USA
| | - Matthijn R Vos
- FEI Company, Nanoport Europe, Achtseweg Noord 5, 5651 GG Eindhoven, the Netherlands
| | - Jörg Bürger
- Institut für Medizinische Physik und Biophysik, Charité-Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany
| | - Thorsten Mielke
- Institut für Medizinische Physik und Biophysik, Charité-Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany; Max-Planck Institut für Molekulare Genetik, Ihnestraße 63-73, 14195 Berlin, Germany
| | - Patrick Scheerer
- Institut für Medizinische Physik und Biophysik, Charité-Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany; Institut für Medizinische Physik und Biophysik, AG Protein X-Ray Crystallography, Charité-Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany
| | - Christian M T Spahn
- Institut für Medizinische Physik und Biophysik, Charité-Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany.
| |
Collapse
|
14
|
Xie P. Origin of multiple intersubunit rotations before EF-G-catalyzed ribosomal translocation through the mRNA with a downstream secondary structure. BMC BIOPHYSICS 2014. [DOI: 10.1186/s13628-014-0012-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
|
15
|
Noel JK, Whitford PC. How Simulations Reveal Dynamics, Disorder, and the Energy Landscapes of Biomolecular Function. Isr J Chem 2014. [DOI: 10.1002/ijch.201400018] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
|
16
|
Ribosome profiling reveals sequence-independent post-initiation pausing as a signature of translation. Cell Res 2014; 24:842-51. [PMID: 24903108 DOI: 10.1038/cr.2014.74] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2014] [Revised: 03/30/2014] [Accepted: 04/24/2014] [Indexed: 02/07/2023] Open
Abstract
The journey of a newly synthesized polypeptide starts in the peptidyltransferase center of the ribosome, from where it traverses the exit tunnel. The interior of the ribosome exit tunnel is neither straight nor smooth. How the ribosome dynamics in vivo is influenced by the exit tunnel is poorly understood. Genome-wide ribosome profiling in mammalian cells reveals elevated ribosome density at the start codon and surprisingly the downstream 5th codon position as well. We found that the highly focused ribosomal pausing shortly after initiation is attributed to the geometry of the exit tunnel, as deletion of the loop region from ribosome protein L4 diminishes translational pausing at the 5th codon position. Unexpectedly, the ribosome variant undergoes translational abandonment shortly after initiation, suggesting that there exists an obligatory step between initiation and elongation commitment. We propose that the post-initiation pausing of ribosomes represents an inherent signature of the translation machinery to ensure productive translation.
Collapse
|
17
|
Margaliot M, Sontag ED, Tuller T. Entrainment to periodic initiation and transition rates in a computational model for gene translation. PLoS One 2014; 9:e96039. [PMID: 24800863 PMCID: PMC4011696 DOI: 10.1371/journal.pone.0096039] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2013] [Accepted: 04/02/2014] [Indexed: 01/09/2023] Open
Abstract
Periodic oscillations play an important role in many biomedical systems. Proper functioning of biological systems that respond to periodic signals requires the ability to synchronize with the periodic excitation. For example, the sleep/wake cycle is a manifestation of an internal timing system that synchronizes to the solar day. In the terminology of systems theory, the biological system must entrain or phase-lock to the periodic excitation. Entrainment is also important in synthetic biology. For example, connecting several artificial biological systems that entrain to a common clock may lead to a well-functioning modular system. The cell-cycle is a periodic program that regulates DNA synthesis and cell division. Recent biological studies suggest that cell-cycle related genes entrain to this periodic program at the gene translation level, leading to periodically-varying protein levels of these genes. The ribosome flow model (RFM) is a deterministic model obtained via a mean-field approximation of a stochastic model from statistical physics that has been used to model numerous processes including ribosome flow along the mRNA. Here we analyze the RFM under the assumption that the initiation and/or transition rates vary periodically with a common period . We show that the ribosome distribution profile in the RFM entrains to this periodic excitation. In particular, the protein synthesis pattern converges to a unique periodic solution with period . To the best of our knowledge, this is the first proof of entrainment in a mathematical model for translation that encapsulates aspects such as initiation and termination rates, ribosomal movement and interactions, and non-homogeneous elongation speeds along the mRNA. Our results support the conjecture that periodic oscillations in tRNA levels and other factors related to the translation process can induce periodic oscillations in protein levels, and may suggest a new approach for re-engineering genetic systems to obtain a desired, periodic, protein synthesis rate.
Collapse
Affiliation(s)
- Michael Margaliot
- School of Electrical Engineering and the Sagol School of Neuroscience, Tel-Aviv University, Tel-Aviv, Israel
| | - Eduardo D. Sontag
- Dept. of Mathematics and Cancer Institute of New Jersey, Rutgers University, Piscataway, New Jersey, United States of America
| | - Tamir Tuller
- Dept. of Biomedical Engineering and the Sagol School of Neuroscience, Tel-Aviv University, Tel-Aviv, Israel
- * E-mail:
| |
Collapse
|
18
|
Whitford PC, Sanbonmatsu KY. Simulating movement of tRNA through the ribosome during hybrid-state formation. J Chem Phys 2014; 139:121919. [PMID: 24089731 DOI: 10.1063/1.4817212] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Biomolecular simulations provide a means for exploring the relationship between flexibility, energetics, structure, and function. With the availability of atomic models from X-ray crystallography and cryoelectron microscopy (cryo-EM), and rapid increases in computing capacity, it is now possible to apply molecular dynamics (MD) simulations to large biomolecular machines, and systematically partition the factors that contribute to function. A large biomolecular complex for which atomic models are available is the ribosome. In the cell, the ribosome reads messenger RNA (mRNA) in order to synthesize proteins. During this essential process, the ribosome undergoes a wide range of conformational rearrangements. One of the most poorly understood transitions is translocation: the process by which transfer RNA (tRNA) molecules move between binding sites inside of the ribosome. The first step of translocation is the adoption of a "hybrid" configuration by the tRNAs, which is accompanied by large-scale rotations in the ribosomal subunits. To illuminate the relationship between these rearrangements, we apply MD simulations using a multi-basin structure-based (SMOG) model, together with targeted molecular dynamics protocols. From 120 simulated transitions, we demonstrate the viability of a particular route during P/E hybrid-state formation, where there is asynchronous movement along rotation and tRNA coordinates. These simulations not only suggest an ordering of events, but they highlight atomic interactions that may influence the kinetics of hybrid-state formation. From these simulations, we also identify steric features (H74 and surrounding residues) encountered during the hybrid transition, and observe that flexibility of the single-stranded 3'-CCA tail is essential for it to reach the endpoint. Together, these simulations provide a set of structural and energetic signatures that suggest strategies for modulating the physical-chemical properties of protein synthesis by the ribosome.
Collapse
Affiliation(s)
- Paul C Whitford
- Department of Physics, Northeastern University, Boston, Massachusetts 02115, USA
| | | |
Collapse
|
19
|
Xie P. Dynamics of tRNA translocation, mRNA translocation and tRNA dissociation during ribosome translation through mRNA secondary structures. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2014; 43:229-40. [DOI: 10.1007/s00249-014-0957-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2013] [Revised: 03/28/2014] [Accepted: 03/31/2014] [Indexed: 11/28/2022]
|
20
|
Affiliation(s)
- Christian M Kaiser
- QB3 Institute, and ‡Department of Chemistry, University of California, Berkeley , Berkeley, California 94720, United States
| | | |
Collapse
|
21
|
Alekhina OM, Vassilenko KS. Translation initiation in eukaryotes: versatility of the scanning model. BIOCHEMISTRY (MOSCOW) 2013; 77:1465-77. [PMID: 23379522 DOI: 10.1134/s0006297912130056] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
It is generally accepted that the initiation of translation in eukaryotes involves the binding of the 40S ribosomal subunit to the capped 5' end of an mRNA and subsequent scanning of 5' UTR in search of an initiation codon. However, until recently this has remained a mere hypothesis. This review describes the novel experimental evidence in support of this classical model. Data on the participation of various factors in the eukaryotic initiation process are summarized. The sequence of initiation events is described in light of the latest experimental data. The existing physical models of scanning are presented. Special attention is paid to discussion of alternative models of eukaryotic initiation of translation. It is demonstrated that the canonical mechanism of initiation is more versatile than previously thought.
Collapse
Affiliation(s)
- O M Alekhina
- Institute of Protein Research, Russian Academy of Sciences, Pushchino, Moscow Region, 142290, Russia
| | | |
Collapse
|
22
|
Abstract
Protein synthesis by the ribosome requires the translocation of transfer RNAs and messenger RNA by one codon after each peptide bond is formed, a reaction that requires ribosomal subunit rotation and is catalyzed by the guanosine triphosphatase (GTPase) elongation factor G (EF-G). We determined 3 angstrom resolution x-ray crystal structures of EF-G complexed with a nonhydrolyzable guanosine 5'-triphosphate (GTP) analog and bound to the Escherichia coli ribosome in different states of ribosomal subunit rotation. The structures reveal that EF-G binding to the ribosome stabilizes switch regions in the GTPase active site, resulting in a compact EF-G conformation that favors an intermediate state of ribosomal subunit rotation. These structures suggest that EF-G controls the translocation reaction by cycles of conformational rigidity and relaxation before and after GTP hydrolysis.
Collapse
Affiliation(s)
- Arto Pulk
- Department of Molecular and Cell Biology, California Institute for Quantitative Biosciences, University of California, Berkeley, CA 94720, USA
| | | |
Collapse
|
23
|
Zhao Y, Chen D, Yue H, French JB, Rufo J, Benkovic SJ, Huang TJ. Lab-on-a-chip technologies for single-molecule studies. LAB ON A CHIP 2013; 13:2183-98. [PMID: 23670195 PMCID: PMC3955889 DOI: 10.1039/c3lc90042h] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Recent developments on various lab-on-a-chip techniques allow miniaturized and integrated devices to perform on-chip single-molecule studies. Fluidic-based platforms that utilize unique microscale fluidic behavior are capable of conducting single-molecule experiments with high sensitivities and throughputs, while biomolecular systems can be studied on-chip using techniques such as DNA curtains, magnetic tweezers, and solid-state nanopores. The advances of these on-chip single-molecule techniques lead to next-generation lab-on-a-chip devices, such as DNA transistors, and single-molecule real-time (SMRT) technology for rapid and low-cost whole genome DNA sequencing. In this Focus article, we will discuss some recent successes in the development of lab-on-a-chip techniques for single-molecule studies and expound our thoughts on the near future of on-chip single-molecule studies.
Collapse
Affiliation(s)
- Yanhui Zhao
- Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, PA 16802 USA
| | - Danqi Chen
- Department of Chemistry, The Pennsylvania State University, University Park, PA 16802 USA
| | - Hongjun Yue
- Department of Chemistry, The Pennsylvania State University, University Park, PA 16802 USA
| | - Jarrod B. French
- Department of Chemistry, The Pennsylvania State University, University Park, PA 16802 USA
| | - Joey Rufo
- Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, PA 16802 USA
| | - Stephen J. Benkovic
- Department of Chemistry, The Pennsylvania State University, University Park, PA 16802 USA
| | - Tony Jun Huang
- Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, PA 16802 USA
| |
Collapse
|
24
|
The paradox of elongation factor 4: highly conserved, yet of no physiological significance? Biochem J 2013; 452:173-81. [DOI: 10.1042/bj20121792] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
LepA [EF4 (elongation factor 4)] is a highly conserved protein found in nearly all known genomes. EF4 triggers back-translocation of the elongating ribosome, causing the translation machinery to move one codon backwards along the mRNA. Knockout of the corresponding gene in various bacteria results in different phenotypes; however, the physiological function of the factor in vivo is unclear. Although functional research on Guf1 (GTPase of unknown function 1), the eukaryotic homologue of EF4, showed that it plays a critical role under suboptimal translation conditions in vivo, its detailed mechanism has yet to be identified. In the present review we briefly cover recent advances in our understanding of EF4, including in vitro structural and biochemical studies, and research on its physiological role in vivo. Lastly, we present a hypothesis for back-translocation and discuss the directions future EF4 research should focus on.
Collapse
|
25
|
Wang L, Wasserman MR, Feldman MB, Altman RB, Blanchard SC. Mechanistic insights into antibiotic action on the ribosome through single-molecule fluorescence imaging. Ann N Y Acad Sci 2013; 1241:E1-16. [PMID: 23419024 DOI: 10.1111/j.1749-6632.2012.06839.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Single-molecule fluorescence imaging has provided unprecedented access to the dynamics of ribosome function, revealing transient intermediate states that are critical to ribosome activity. Imaging platforms have now been developed that are capable of probing many hundreds of molecules simultaneously at temporal and spatial resolutions approaching the sub-millisecond time and the sub-nanometer scales. These advances enable both steady- and pre-steady state measurements of individual steps in the translation process as well as processive reactions. The data generated using these methods have yielded new, quantitative structural and kinetic insights into ribosomal activity. They have also shed light on the mechanisms of antibiotic targeting the translation apparatus, revealing features of the structure-function relationship that would be difficult to obtain by other means. This review provides an overview of the types of information that can be obtained using such imaging platforms and a blueprint for using the technique to assess how small-molecule antibiotics alter macromolecular functions.
Collapse
Affiliation(s)
- Leyi Wang
- Department of Physiology and Biophysics, Weill Cornell Medical College, New York, NY 10065, USA
| | | | | | | | | |
Collapse
|
26
|
Valásek LS. 'Ribozoomin'--translation initiation from the perspective of the ribosome-bound eukaryotic initiation factors (eIFs). Curr Protein Pept Sci 2013; 13:305-30. [PMID: 22708493 PMCID: PMC3434475 DOI: 10.2174/138920312801619385] [Citation(s) in RCA: 103] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2011] [Revised: 01/16/2012] [Accepted: 02/16/2012] [Indexed: 02/05/2023]
Abstract
Protein synthesis is a fundamental biological mechanism bringing the DNA-encoded genetic information into
life by its translation into molecular effectors - proteins. The initiation phase of translation is one of the key points of gene
regulation in eukaryotes, playing a role in processes from neuronal function to development. Indeed, the importance of the
study of protein synthesis is increasing with the growing list of genetic diseases caused by mutations that affect mRNA
translation. To grasp how this regulation is achieved or altered in the latter case, we must first understand the molecular
details of all underlying processes of the translational cycle with the main focus put on its initiation. In this review I discuss
recent advances in our comprehension of the molecular basis of particular initiation reactions set into the context of
how and where individual eIFs bind to the small ribosomal subunit in the pre-initiation complex. I also summarize our
current knowledge on how eukaryotic initiation factor eIF3 controls gene expression in the gene-specific manner via reinitiation.
Collapse
Affiliation(s)
- Leos Shivaya Valásek
- Laboratory of Eukaryotic Gene Regulation, Institute of Microbiology AS CR, Prague, Czech Republic.
| |
Collapse
|
27
|
Xie P. Dynamics of tRNA occupancy and dissociation during translation by the ribosome. J Theor Biol 2013; 316:49-60. [DOI: 10.1016/j.jtbi.2012.09.023] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2012] [Revised: 09/17/2012] [Accepted: 09/18/2012] [Indexed: 12/23/2022]
|
28
|
Xie P. Model of ribosome translation and mRNA unwinding. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2012; 42:347-54. [DOI: 10.1007/s00249-012-0879-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2012] [Revised: 11/19/2012] [Accepted: 11/29/2012] [Indexed: 10/27/2022]
|
29
|
Evolutionary conservation of codon optimality reveals hidden signatures of cotranslational folding. Nat Struct Mol Biol 2012; 20:237-43. [PMID: 23262490 PMCID: PMC3565066 DOI: 10.1038/nsmb.2466] [Citation(s) in RCA: 344] [Impact Index Per Article: 28.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2012] [Accepted: 11/12/2012] [Indexed: 01/01/2023]
Abstract
The choice of codons can influence local translation kinetics during protein synthesis. Whether codon preference is linked to co-translational regulation of polypeptide folding remains unclear. Here, we derive a revised translational efficiency scale that incorporates the competition between tRNA supply and demand. Applying this scale to ten closely related yeasts, we uncover the evolutionary conservation of codon optimality in eukaryotes. This analysis reveals universal patterns of conserved optimal and nonoptimal codons, often in clusters, which associate with the secondary structure of the translated polypeptides independent of the levels of expression. Our analysis suggests an evolved function for codon optimality in regulating the rhythm of elongation to facilitate co-translational polypeptide folding, beyond its previously proposed role of adapting to the cost of expression. These findings establish how mRNA sequences are generally under selection to optimize the co-translational folding of corresponding polypeptides.
Collapse
|
30
|
Abstract
Elongation factor-G-catalyzed translocation of mRNA and tRNAs during protein synthesis involves large-scale conformational changes in the ribosome. Formation of hybrid-state intermediates is coupled to counterclockwise (forward) rotation of the body of the 30S subunit. Recent structural studies implicate intrasubunit rotation of the 30S head in translocation. Here, we observe rotation of the head during translocation in real time using ensemble stopped-flow FRET with ribosomes containing fluorescent probes attached to specific positions in the head and body of the 30S subunit. Our results allow ordering of the rates of movement of the 30S subunit body and head during translocation: body forward > head forward > head reverse ≥ body reverse. The rate of quenching of pyrene-labeled mRNA is consistent with coupling of mRNA translocation to head rotation.
Collapse
|
31
|
Teng CH, Lionberger TA, Zhang J, Meyhöfer E, Ku PC. Fabrication of nanoscale zero-mode waveguides using microlithography for single molecule sensing. NANOTECHNOLOGY 2012; 23:455301. [PMID: 23085680 DOI: 10.1088/0957-4484/23/45/455301] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
We present a novel approach to the fabrication of zero-mode waveguides (ZMWs) using inexpensive processing techniques. Our method is capable of rapid fabrication of circular nanoapertures with diameters ranging from 70 nm to 2 μm, allowing us to perform a detailed characterization of the dependence of the fluorescence emission on the waveguide diameter. We also validated the use of the fabricated ZMWs by detecting single molecule binding events with a signal-to-noise ratio of ten.
Collapse
Affiliation(s)
- Chu-Hsiang Teng
- Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, MI 48105, USA
| | | | | | | | | |
Collapse
|
32
|
Mitkevich VA, Shyp V, Petrushanko IY, Soosaar A, Atkinson GC, Tenson T, Makarov AA, Hauryliuk V. GTPases IF2 and EF-G bind GDP and the SRL RNA in a mutually exclusive manner. Sci Rep 2012; 2:843. [PMID: 23150791 PMCID: PMC3496166 DOI: 10.1038/srep00843] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2012] [Accepted: 10/17/2012] [Indexed: 01/05/2023] Open
Abstract
Translational GTPases (trGTPases) are involved in all four stages of protein biosynthesis: initiation, elongation, termination and ribosome recycling. The trGTPases Initiation Factor 2 (IF2) and Elongation Factor G (EF-G) respectively orchestrate initiation complex formation and translocation of the peptidyl-tRNA:mRNA complex through the bacterial ribosome. The ribosome regulates the GTPase cycle and efficiently discriminates between the GDP- and GTP-bound forms of these proteins. Using Isothermal Titration Calorimetry, we have investigated interactions of IF2 and EF-G with the sarcin-ricin loop of the 23S rRNA, a crucial element of the GTPase-associated center of the ribosome. We show that binding of IF2 and EF-G to a 27 nucleotide RNA fragment mimicking the sarcin-ricin loop is mutually exclusive with that of GDP, but not of GTP, providing a mechanism for destabilization of the ribosome-bound GDP forms of translational GTPases.
Collapse
Affiliation(s)
- Vladimir A Mitkevich
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow 119991, Russia
| | | | | | | | | | | | | | | |
Collapse
|
33
|
Chen J, Tsai A, O'Leary SE, Petrov A, Puglisi JD. Unraveling the dynamics of ribosome translocation. Curr Opin Struct Biol 2012; 22:804-14. [PMID: 23142574 DOI: 10.1016/j.sbi.2012.09.004] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2012] [Revised: 09/07/2012] [Accepted: 09/12/2012] [Indexed: 10/27/2022]
Abstract
Translocation is one of the key events in translation, requiring large-scale conformational changes in the ribosome, movements of two transfer RNAs (tRNAs) across a distance of more than 20Å, and the coupled movement of the messenger RNA (mRNA) by one codon, completing one cycle of peptide-chain elongation. Translocation is catalyzed by elongation factor G (EF-G in bacteria), which hydrolyzes GTP in the process. However, how the conformational rearrangements of the ribosome actually drive the movements of the tRNAs and how EF-G GTP hydrolysis plays a role in this process are still unclear. Fluorescence methods, both single-molecule and bulk, have provided a dynamic view of translocation, allowing us to follow the different conformational changes of the ribosome in real-time. The application of electron microscopy has revealed new conformational intermediates during translocation and important structural rearrangements in the ribosome that drive tRNA movement, while computational approaches have added quantitative views of the translational pathway. These recent advances shed light on the process of translocation, providing insight on how to resolve the different descriptions of translocation in the current literature.
Collapse
Affiliation(s)
- Jin Chen
- Department of Applied Physics, Stanford University, Stanford, CA 94305-4090, USA
| | | | | | | | | |
Collapse
|
34
|
Studying genomic processes at the single-molecule level: introducing the tools and applications. Nat Rev Genet 2012; 14:9-22. [DOI: 10.1038/nrg3316] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
|
35
|
Réblová K, Šponer J, Lankaš F. Structure and mechanical properties of the ribosomal L1 stalk three-way junction. Nucleic Acids Res 2012; 40:6290-303. [PMID: 22451682 PMCID: PMC3401443 DOI: 10.1093/nar/gks258] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2012] [Revised: 03/07/2012] [Accepted: 03/07/2012] [Indexed: 01/06/2023] Open
Abstract
The L1 stalk is a key mobile element of the large ribosomal subunit which interacts with tRNA during translocation. Here, we investigate the structure and mechanical properties of the rRNA H76/H75/H79 three-way junction at the base of the L1 stalk from four different prokaryotic organisms. We propose a coarse-grained elastic model and parameterize it using large-scale atomistic molecular dynamics simulations. Global properties of the junction are well described by a model in which the H76 helix is represented by a straight, isotropically flexible elastic rod, while the junction core is represented by an isotropically flexible spherical hinge. Both the core and the helix contribute substantially to the overall H76 bending fluctuations. The presence of wobble pairs in H76 does not induce any increased flexibility or anisotropy to the helix. The half-closed conformation of the L1 stalk seems to be accessible by thermal fluctuations of the junction itself, without any long-range allosteric effects. Bending fluctuations of H76 with a bulge introduced in it suggest a rationale for the precise position of the bulge in eukaryotes. Our elastic model can be generalized to other RNA junctions found in biological systems or in nanotechnology.
Collapse
Affiliation(s)
- Kamila Réblová
- Institute of Biophysics, Academy of Sciences of the Czech Republic, Královopolská 135, 612 65 Brno, CEITEC—Central European Institute of Technology, Masaryk University, Campus Bohunice, Kamenice 5, 625 00 Brno and Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo nám. 2, 166 10 Praha 6, Czech Republic
| | - Jiří Šponer
- Institute of Biophysics, Academy of Sciences of the Czech Republic, Královopolská 135, 612 65 Brno, CEITEC—Central European Institute of Technology, Masaryk University, Campus Bohunice, Kamenice 5, 625 00 Brno and Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo nám. 2, 166 10 Praha 6, Czech Republic
| | - Filip Lankaš
- Institute of Biophysics, Academy of Sciences of the Czech Republic, Královopolská 135, 612 65 Brno, CEITEC—Central European Institute of Technology, Masaryk University, Campus Bohunice, Kamenice 5, 625 00 Brno and Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo nám. 2, 166 10 Praha 6, Czech Republic
| |
Collapse
|
36
|
Zhang Y, Berndt U, Gölz H, Tais A, Oellerer S, Wölfle T, Fitzke E, Rospert S. NAC functions as a modulator of SRP during the early steps of protein targeting to the endoplasmic reticulum. Mol Biol Cell 2012; 23:3027-40. [PMID: 22740632 PMCID: PMC3418300 DOI: 10.1091/mbc.e12-02-0112] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
NAC acts as a modulator of SRP function. It can bind to signal sequences directly. SRP initially displaces NAC from RNCs; however, when the signal sequence emerges, trimeric NAC·RNC·SRP complexes form. Upon docking NAC·RNC·SRP complexes to the ER, NAC remains bound, allowing NAC to shield cytosolically exposed nascent chain domains. Nascent polypeptide-associated complex (NAC) was initially found to bind to any segment of the nascent chain except signal sequences. In this way, NAC is believed to prevent mistargeting due to binding of signal recognition particle (SRP) to signalless ribosome nascent chain complexes (RNCs). Here we revisit the interplay between NAC and SRP. NAC does not affect SRP function with respect to signalless RNCs; however, NAC does affect SRP function with respect to RNCs targeted to the endoplasmic reticulum (ER). First, early recruitment of SRP to RNCs containing a signal sequence within the ribosomal tunnel is NAC dependent. Second, NAC is able to directly and tightly bind to nascent signal sequences. Third, SRP initially displaces NAC from RNCs; however, when the signal sequence emerges further, trimeric NAC·RNC·SRP complexes form. Fourth, upon docking to the ER membrane NAC remains bound to RNCs, allowing NAC to shield cytosolically exposed nascent chain domains not only before but also during cotranslational translocation. The combined data indicate a functional interplay between NAC and SRP on ER-targeted RNCs, which is based on the ability of the two complexes to bind simultaneously to distinct segments of a single nascent chain.
Collapse
Affiliation(s)
- Ying Zhang
- Institute of Biochemistry and Molecular Biology, Centre for Biochemistry and Molecular Cell Research, University of Freiburg, Freiburg, Germany
| | | | | | | | | | | | | | | |
Collapse
|
37
|
Affiliation(s)
- Peter B. Moore
- Department of Chemistry, Yale University, New Haven, Connecticut 06520-8107;
| |
Collapse
|
38
|
Mackereth CD, Sattler M. Dynamics in multi-domain protein recognition of RNA. Curr Opin Struct Biol 2012; 22:287-96. [DOI: 10.1016/j.sbi.2012.03.013] [Citation(s) in RCA: 90] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2012] [Accepted: 03/25/2012] [Indexed: 12/28/2022]
|
39
|
Real-time evidence for EF-G-induced dynamics of helix 44 in 16S rRNA. J Mol Biol 2012; 422:45-57. [PMID: 22634282 DOI: 10.1016/j.jmb.2012.05.012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2011] [Revised: 05/03/2012] [Accepted: 05/08/2012] [Indexed: 11/21/2022]
Abstract
The penultimate stem-loop of 16S ribosomal RNA (rRNA), helix 44, plays a central role in ribosome function. Using time-resolved dimethyl sulfate (DMS) probing, we have analyzed time-dependent modifications that occur at specific bases in this helix near the decoding region, resulting from the binding of elongation factor G (EF-G) in various forms. When EF-G-GTP is bound to 70S ribosomes, bases A1492 and A1493 are immediately protected, while other bases in the region show either no change or enhanced modification. When apo-EF-G is bound to 70S ribosomes and GTP is added, substantial transient time-dependent enhancement occurs at bases A1492 and A1493, with somewhat less enhancement occurring at base A1483, all in the first 45 ms. When mRNA and deacylated tRNAs are bound to the 70S ribosome and EF-G-GTP is added, bases A1492 and A1493 again show substantial and continued enhancement, while bases A1408, A1413, and A1418 all show time-dependent protection. These results provide primary, real-time evidence that EF-G induces direct or indirect structural changes in this region as EF-G is bound and as GTP is hydrolyzed.
Collapse
|
40
|
Fourmy D, Yoshizawa S. Protein-RNA footprinting: an evolving tool. WILEY INTERDISCIPLINARY REVIEWS-RNA 2012; 3:557-66. [PMID: 22566372 DOI: 10.1002/wrna.1119] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
As more RNA molecules with important cellular functions are discovered, there is a strong need to characterize their structures, functions, and interactions. Chemical and enzymatic footprinting methods are used to map RNA secondary and tertiary structure, to monitor ligand interactions and conformational changes, and in the study of protein-RNA interactions. These methods provide data at single-nucleotide resolution that nicely complements the structural information available from X-ray diffraction, nuclear magnetic resonance spectroscopy (NMR), or cryo-electron microscopy. Footprinting methods also complement the dynamic information derived from single-molecule Förster resonance energy transfer. RNA footprinting tools have been used for decades, but we have recently seen spectacular advances, for instance, the use in combination with massive parallel sequencing techniques. Large libraries of RNA molecules (small or large in size) can now be probed in high-throughput manner when RNA footprinting methods are combined with fluorescent probe technologies and automation. In this article, after a brief historical overview, we summarize recent advances in RNA-protein footprinting methodologies that now integrate tools for massive parallel analysis.
Collapse
Affiliation(s)
- Dominique Fourmy
- Centre de Génétique Moléculaire UPR 3404, CNRS, Université Paris-Sud, Gif-sur-Yvette, France.
| | | |
Collapse
|
41
|
Yoshizawa S. Micro and nanotechnological tools for study of RNA. Biochimie 2012; 94:1588-94. [PMID: 22484393 DOI: 10.1016/j.biochi.2012.03.018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2012] [Accepted: 03/22/2012] [Indexed: 11/16/2022]
Abstract
Micro and nanotechnologies have originally contributed to engineering, especially in electronics. These technologies enable fabrication and assembly of materials at micrometer and nanometer scales and the manipulation of nano-objects. The power of these technologies has now been exploited in analyzes of biologically relevant molecules. In this review, the use of micro and nanotechnological tools in RNA research is described.
Collapse
Affiliation(s)
- Satoko Yoshizawa
- Centre de Génétique Moléculaire UPR 3404, CNRS, Université Paris-Sud, FRC3115 1 Ave de la Terrasse, 91190 Gif-sur-Yvette, France.
| |
Collapse
|
42
|
Rosenblum G, Chen C, Kaur J, Cui X, Goldman YE, Cooperman BS. Real-time assay for testing components of protein synthesis. Nucleic Acids Res 2012; 40:e88. [PMID: 22422844 PMCID: PMC3384345 DOI: 10.1093/nar/gks232] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
We present a flexible, real-time-coupled transcription–translation assay that involves the continuous monitoring of fluorescent Emerald GFP formation. Along with numerical simulation of a reaction kinetics model, the assay permits quantitative estimation of the effects on full-length protein synthesis of various additions, subtractions or substitutions to the protein synthesis machinery. Since the assay uses continuous fluorescence monitoring, it is much simpler and more rapid than other assays of protein synthesis and is compatible with high-throughput formats. Straightforward alterations of the assay permit determination of (i) the fraction of ribosomes in a cell-free protein synthesis kit that is active in full-length protein synthesis and (ii) the relative activities in supporting protein synthesis of modified (e.g. mutated, fluorescent-labeled) exogenous components (ribosomes, amino acid-specific tRNAs) that replace the corresponding endogenous components. Ribosomes containing fluorescent-labeled L11 and tRNAs labeled with fluorophores in the D-loop retain substantial activity. In the latter case, the extent of activity loss correlates with a combination of steric bulk and hydrophobicity of the fluorophore.
Collapse
Affiliation(s)
- Gabriel Rosenblum
- The Department of Chemistry, University of Pennsylvania, 231 South 34th Street, Philadelphia, Pennsylvania 19104, USA
| | | | | | | | | | | |
Collapse
|
43
|
In vitro and in vivo single-molecule fluorescence imaging of ribosome-catalyzed protein synthesis. Curr Opin Chem Biol 2011; 15:853-63. [PMID: 22104181 DOI: 10.1016/j.cbpa.2011.11.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2011] [Revised: 11/01/2011] [Accepted: 11/01/2011] [Indexed: 11/22/2022]
Abstract
Combined with the availability of highly purified, fluorescently labeled in vitro translation systems, the advent of single-molecule fluorescence imaging has ushered in a new era in high-resolution mechanistic studies of ribosome-catalyzed protein synthesis, or translation. Together with ensemble biochemical investigations of translation and structural studies of functional ribosomal complexes, in vitro single-molecule fluorescence imaging of protein synthesis is providing unique mechanistic insight into this fundamental biological process. More recently, rapidly evolving breakthroughs in fluorescence-based molecular imaging in live cells with sub-diffraction-limit spatial resolution and ever-increasing temporal resolution provide great promise for conducting mechanistic studies of translation and its regulation in living cells. Here we review the remarkable recent progress that has been made in these fields, highlight important mechanistic insights that have been gleaned from these studies thus far, and discuss what we envision lies ahead as these approaches continue to evolve and expand to address increasingly complex mechanistic and regulatory aspects of translation.
Collapse
|
44
|
Excited states of ribosome translocation revealed through integrative molecular modeling. Proc Natl Acad Sci U S A 2011; 108:18943-8. [PMID: 22080606 DOI: 10.1073/pnas.1108363108] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The dynamic nature of biomolecules leads to significant challenges when characterizing the structural properties associated with function. While X-ray crystallography and imaging techniques (such as cryo-electron microscopy) can reveal the structural details of stable molecular complexes, strategies must be developed to characterize configurations that exhibit only marginal stability (such as intermediates) or configurations that do not correspond to minima on the energy landscape (such as transition-state ensembles). Here, we present a methodology (MDfit) that utilizes molecular dynamics simulations to generate configurations of excited states that are consistent with available biophysical and biochemical measurements. To demonstrate the approach, we present a sequence of configurations that are suggested to be associated with transfer RNA (tRNA) movement through the ribosome (translocation). The models were constructed by combining information from X-ray crystallography, cryo-electron microscopy, and biochemical data. These models provide a structural framework for translocation that may be further investigated experimentally and theoretically to determine the precise energetic character of each configuration and the transition dynamics between them.
Collapse
|
45
|
Grossman M, Sela-Passwell N, Sagi I. Achieving broad molecular insights into dynamic protein interactions by integrated structural-kinetic approaches. Curr Opin Struct Biol 2011; 21:678-85. [PMID: 21945040 DOI: 10.1016/j.sbi.2011.07.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2011] [Revised: 07/21/2011] [Accepted: 07/31/2011] [Indexed: 11/30/2022]
Abstract
A network of dynamic protein interactions with their protein partners, substrates, and ligands is known to be crucial for biological function. Revealing molecular and structural-based mechanisms at atomic resolution and in real-time is fundamental for achieving a basic understanding of cellular processes. These technically challenging goals may be achieved by combining time-resolved spectroscopic and structural-kinetic tools, thus providing broad insights into specific molecular events over a wide range of timescales. Here we review representative studies utilizing such an integrated real-time structural approach designed to reveal molecular mechanisms underlying protein interactions at atomic resolution.
Collapse
Affiliation(s)
- Moran Grossman
- Departments of Structural Biology and Biological Regulation, The Weizmann Institute of Science, Rehovot 76100, Israel
| | | | | |
Collapse
|